Question

Veterinarians at Texas A&M University were interested in learning about the proportion of people in College Station that adopted animals from the Humane Society. The veterinarians had calculated that they needed to sample 1940 people to achieve a specific margin of error with a 99% confidence level. Assuming they believed the population proportion was 0.7, what margin of error did they use to calculate the needed sample size?

Selected Answer:	0.019
Answers:	0.020
	More information is needed to answer this question.
	0.019
	0.027
	0.017

Do you need the formula for the population mean or population proportion?

Answer 1

Solution :

Given that,

n = 1940

Point estimate = sample proportion = = 0.7

1 -   = 1- 0.7=0.3

At 99% confidence level the z is ,

  = 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

Z_/2 = Z_0.005 = 2.576 ( Using z table )

  Margin of error = E = Z/2   * (((( * (1 - )) / n)

= 2.576* (((0.7*0.3) /1940 )

E = 0.027